Programmed cell death and aerenchyma formation in roots

Drew, M. C.; He, Chongbo; Morgan, Page W.

doi:10.1016/s1360-1385(00)01570-3

Cited by 513 publications

(436 citation statements)

References 32 publications

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“…Hypoxia-induced aerenchyma formation is a well documented adaptation required for plant roots to maintain oxygen status. Aerenchyma differentiation requires elimination of root cortical cells that is mediated through PCD [24][25][26]. Similarly to the results presented here for rice, barley seedlings develop new roots after salt induced cell death causes senescence of the primary root [27].…”

Section: Discussionsupporting

confidence: 74%

“…Programmed cell death (PCD) or apoptosis occurs during development and in response to different environmental cues [1][2][3][4][5][6]. Apoptosis exhibits several distinct morphological features, including condensation of cytoplasm, fragmentation of nucleosomal DNA, condensation of nuclear chromatin, membrane blabbing, and appearance of apoptotic bodies [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

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Salinity Induced Apoptosis in Root Meristematic Cells ofRice

Yazdani¹,

Mahdieh²

2012

IJBBB

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Abstract-Salt stress is one of the most serious problems in agriculture and can induce apoptosis in plants. Cell death is induced by two modes: apoptosis and necrosis. We used a TUNEL assay and DNA gel electrophoresis on NaCl-treated cells of rice root to morphologically distinguish the mode of cell death in salt-sensitive and salt-tolerant rice cultivars. The results indicated that 500 mmol/L NaCl treatments could lead to specific features of apoptosis in root tips in both cultivars, such as DNA ladder, nuclear condense and deformation, and transferase mediated dUTP nick end labeling positive reaction, which were initiated at 4h of treatment and progressed thereafter.

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Section: Discussionsupporting

confidence: 74%

Section: Introductionmentioning

confidence: 99%

Salinity Induced Apoptosis in Root Meristematic Cells ofRice

Yazdani¹,

Mahdieh²

2012

IJBBB

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“…Much of the role that ethylene plays has been elucidated since these early observations ( Figure 2; Drew et al, 2000). He et al (1994) described an increase in the root tips of maize of the enzyme that is largely responsible for the rate of ethylene biosynthesis, i.e.…”

Section: Hypoxia and Ethylenementioning

confidence: 99%

Acclimation to soil flooding — sensing and signal-transduction

Visser

Voesenek

2005

Plant Ecophysiology

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Flooding results in major changes in the soil environment. The slow diffusion rate of gases in water limits the oxygen supply, which affects aerobic root respiration as well as many (bio)geochemical processes in the soil. Plants from habitats subject to flooding have developed several ways to acclimate to these growth-inhibiting conditions, ranging from pathways that enable anaerobic metabolism to specific morphological and anatomical structures that prevent oxygen shortage. In order to acclimate in a timely manner, it is crucial that a flooding event is accurately sensed by the plant. Sensing may largely occur in two ways: by the decrease of oxygen concentration, and by an increase in ethylene. Although ethylene sensing is now well understood, progress in unraveling the sensing of oxygen has been made only recently. With respect to the signal-transduction pathways, two types of acclimation have received most attention. Aerenchyma formation, to promote gas diffusion through the roots, seems largely under control of ethylene, whereas adventitious root development appears to be induced by an interaction between ethylene and auxin. Parts of these pathways have been described for a range of species, but a complete overview is not yet available. The use of molecular-genetic approaches may fill the gaps in our knowledge, but a lack of suitable model species may hamper further progress.

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“…However, when hydromorphic soils become flooded or carry excessive humidity the availability of O 2 diminishes, in view of the diffusion rate being 10,000 times less than in air and the dissolved concentration in water being some 30 times lower than in air (Armstrong et al, 1994). Total depletion of dissolved O 2 is possible within 24 h of flooding, due to its consumption by micro-organisms and plants (Armstrong et al, 1994, Drew et al, 2000Liesack et al 2000). Flooding of the soil can lead to an accumulation of NH 4 + , since the absence of O 2 interrupts nitrification of NH 4 + , while NO 3 -is the first oxidized compound in the soil to be utilized by anaerobic micro-organisms (Marschner, 1995;Sousa et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

“…Tolerance to flooding can arise in the long-term with the formation of aerenchyma, an important morphological adaptation resulting in increased availability of oxygen to submerged roots (Drew et al, 2000). However, in soybean at least, nitrate must exert its beneficial effect on flooding tolerance by other mechanisms since it was found to diminish the amount of aerenchyma formed (Bacanamwo and Purcell, 1999a).…”

Section: Introductionmentioning

confidence: 99%

Amino acid and ureide transport in the xylem of symbiotic soybean plants during short-term flooding of the root system in the presence of different sources of nitrogen

Thomas

Sodek

2006

Braz. J. Plant Physiol.

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The transport of organic N compounds to the shoot in the xylem sap of nodulated soybean plants was investigated in an attempt to better understand the changes in N metabolism under root hypoxia (first 5 days of flooding), with different sources of N in the medium. NO 3 -is beneficial for tolerance of plants to waterlogging, whereas other N sources such as NH 4 + and NH 4 NO 3, are not. Nevertheless, in the presence of NH 4 + high levels of amino acids were transported in the xylem, consistent with its assimilation. Some increase in the transport of amino acids was also seen with NO 3 -nutrition during waterlogging, but not with N-free medium. Ureide transport in the xylem was severely reduced during waterlogging, consistent with impaired N 2 fixation under these conditions. The relative proportions of some amino acids in the xylem showed dramatic changes during treatment. Alanine increased tremendously under root hypoxia, especially with NH 4 + as N source, where it reached near 70 % of the total amino acids present. Aspartic acid, on the other hand, dropped to very low levels and was inversely related to alanine levels, consistent with this amino acid being the immediate source of N for alanine synthesis. Glutamine levels also fell to a larger or lesser extent, depending on the N source present. The changes in asparagine, one of the prominent amino acids of the xylem sap, were most outstanding in the treatment with NO 3 -, where they showed a large increase, characteristic of plants switching from dependence on N 2 fixation to NO 3 -assimilation. The data indicate that the lesser effectiveness of NH 4 + during waterlogging, in contrast to NO 3 -, involves restricted amino acids metabolism, and may result from energy metabolism being directed towards NH 4 + detoxification. Key words: Glycine max, alanine, hypoxia, N metabolism.Transporte de aminoácidos e ureídeos no xilema de plantas de soja simbióticas sob curto período de alagamento do sistema radicular com diferentes fontes de nitrogênio: O transporte de compostos nitrogenados orgânicos à parte aérea de plantas de soja, através da seiva do xilema, foi investigado para melhor entender as mudanças no metabolismo do sistema radicular sob hipoxia (primeiros 5 dias de alagamento) e com diferentes fontes de N no meio. O NO 3 -é benéfico à tolerância das plantas ao alagamento, enquanto que outras fontes de N, como o NH 4 NO 3 e o NH 4 , não são. Contudo, na presença de NH 4 + elevados níveis de aminoácidos foram transportados no xilema, demonstrando sua assimilação. Algum aumento no transporte de aminoácidos também ocorreu com a presença de NO 3 -durante o alagamento, mas não na ausência de N no meio. O transporte de ureídeos no xilema foi severamente reduzido durante o alagamento, demonstrando a inibição da fixação de N 2 nessa condição. As proporções relativas de alguns aminoácidos no xilema demonstraram mudanças drásticas durante os tratamentos. Alanina aumentou acentuadamente com o sistema radicular sob hipoxia, especialmente com NH 4 + como fonte de N, quando e...

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Programmed cell death and aerenchyma formation in roots

Cited by 513 publications

References 32 publications

Salinity Induced Apoptosis in Root Meristematic Cells ofRice

Salinity Induced Apoptosis in Root Meristematic Cells ofRice

Acclimation to soil flooding — sensing and signal-transduction

Amino acid and ureide transport in the xylem of symbiotic soybean plants during short-term flooding of the root system in the presence of different sources of nitrogen

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